The present invention relates in general to providing multimedia services from a data network such as the Internet to users of cable systems, and, more specifically, to increasing the users' access to voice and video multimedia services with improved network performance.
PacketCable standards have been developed to provide a cable system/IP network architecture to deliver point-to-point multimedia services, such as voice over IP (VoIP). The architecture includes a multimedia terminal adapter (MTA) which may be integrated with a cable modem or connected to a separate cable modem. The MTA performs signal manipulations (e.g., encoding/decoding and A/D and D/A conversion) and implements various network protocols.
The various network services that may be provided to the cable customer typically require corresponding applications to be installed in the MTA. A standard software environment known as the OpenCable applications platform (OCAP) has been developed to encourage compatibility and reduce hardware/software costs. OCAP includes a set of application programming interfaces (API's) that provide an operating system (i.e., middleware) for the application programs themselves. The API's comprise Java software packages that provide program access to basic system resources. An OCAP compliant application program can thus run on any OCAP compatible devices to access network services and multimedia content, among other functions.
The types of services contemplated to be implemented using OCAP include various interactive services such as electronic program guides, voice over IP (VoIP), video telephony, video on demand (VOD), and other services. However, the OCAP model does not enable other types of client/server applications.
One known means of establishing point-to-point communication sessions via the Internet is by using the session initiation protocol (SIP). The SIP protocol performs various functions including determining location of a target endpoint, determining media format capabilities of the session endpoints (using the session description protocol, “SDP”), determining availability of a target endpoint, establishing an active session between endpoints, and terminating an active session. MTA's have become available which support the SIP protocol and which allow access to telephony services by acting as a SIP client. However, these methods provide limited access to SIP-based services by requiring that any particular service be preprogrammed in the MTA and they cannot provide adequate control over communication parameters, such as QoS parameters.